The present invention relates generally to cross bars and more particularly to a cross bar for attaching to a conductors (strap) in a rotary contact circuit breaker.
Circuit breakers are one of a variety of overcurrent protective devices used for circuit protection and isolation. The basic function of a circuit breaker is to provide electrical system protection whenever an electrical abnormality occurs in any part of the system. In a rotary contact circuit breaker, current enters the system from a power source. The current passes through a line strap to a fixed contact mounted on the line strap and then to a moveable contact. The moveable contact is fixedly attached to an arm, and the arm is mounted to a rotor that in turn is rotatably mounted in a cassette. As long as the fixed contact is in physical contact with the moveable contact, the current passes from the fixed contact to the moveable contact and out of the circuit breaker to downstream electrical devices.
In the event of an extremely high overcurrent condition (e.g. a short circuit), electromagnetic forces are generated between the fixed and moveable contacts. These electromagnetic forces repel the movable contact away from the fixed contact. Because the moveable contact is fixedly attached to a rotating arm, the arm pivots and physically separates the fixed contact from the moveable contact.
Once activated, the circuit breaker operating mechanism separates a pair of main contacts to stop the flow of current in the protected circuit. Conventional trip units act directly upon the circuit breaker operating mechanism to activate the circuit breaker operating mechanism.
During an interruption event, such as a short circuit, high levels of energy travel through the load side strap (conductor). During these events, the load side conductor experiences forces causing undesirable rotational and translational movement of the conductor. Typically, load side conductor connections are fixedly supported within the circuit breaker case to absorb the energy passing through during interruption as well as during assembly when electrical connections are made to the load side conductors. However, to fixedly support the load side strap can require additional space in which to provide and mount a supporting structure for the load side conductors and connections.
The above discussed and other drawbacks and deficiencies are overcome or alleviated by a cross bar for securely retaining a conductive strap to a circuit breaker case is disclosed. The cross bar comprises a main body portion having a first end and a second end. The main body portion is configured for attachment to the conductive strap and the first and second ends are configured for attachment to the circuit breaker case. The cross bar secures the conductive strap in mounting stability to the circuit breaker case to prevent movement of the conductive strap relative to the case.